Vehicles with at least an electric powertrain, such as electric vehicles or hybrid vehicles, carry a battery pack composed of an array of closely positioned modules, each module being in series with one another, to provide a combined energy of desired level.
To be more compact, to improve energy storage density and to adapt to some particular geometrical spaces, some battery packs comprise a plurality of arrays, or stacks of modules.
During operation, when some electrical energy is transferred in or out from the stacks of modules, during charge and discharge cycles, some heat is produced by the chemical reactions that take place within the modules.
For optimized performance and sustained longevity, the modules have to be maintained during operation in a predetermined operating temperature range, and the temperature difference between each module needs to be as little as possible.
It is a problem with the battery pack known from the prior art, to ensure that these requirements are fulfilled for all the modules, especially when the battery packs become large and comprise a large number of modules.
It is a general object of the invention to provide a battery pack with an improved temperature control and a pack in which the heat transfer from the modules is enhanced.